Bombesin-like peptide receptors are widely distributed in mammalian nervous system, GI-tract and lung. Their expression in various mammalian neoplasms indicates their potential significance to develop diagnostic and therapeutic applications. To date, three mammalian BLP receptors were isolated. However, recently we have isolated amphibian bombesin receptor and discovered a new branch of BLP receptors in amphibians. Ranatensin is a member in the BLP family and shows distinct pharmacology from bombesin. To isolate ranatensin receptor from Rana pipiens, we used RT-PCR and cDNA library screening. Sequence analysis reveals that it is highly homologous to the amphibian bombesin receptor. We are currently expressing the receptor in oocytes to determine the pharmacology. The presence of distinct bombesin and ranatensin receptors indicates that a mammalian receptor homologous to this branch may exist. Using similar strategies, we are currently looking for the mammalian homologs for ranatensin receptor.